1. Field of the Invention
The present invention relates to an inkjet printing apparatus and an inkjet printing method, and more particularly to an inkjet printing apparatus and an inkjet printing method of printing by depositing a transparent liquid onto a blank background portion.
2. Description of the Related Art
If an aqueous ink (ink containing water as a solvent) is used for printing by an inkjet method onto general printing paper, then there is a possibility that the portion where ink has been deposited deforms (producing curl, cockling, etc.) due to the solvent (principally, water), and hence the quality of the printed object is impaired. Furthermore, even if there is slight deformation which does not affect quality, in the case of a system where paper is conveyed by suctioning (for example, a system where the paper is conveyed on a drum or on a belt), there is a possibility that the deformation of the paper will accumulate if the paper is progressively suctioned from the leading end thereof and wrinkles will occur in the trailing end portion thereof.
Japanese Patent Application Publication No. 2004-58308 and Japanese Patent Application Publication No. 2008-290286 propose equalizing the amount of moisture in an entire sheet of paper and thereby eliminating local deformation of the paper, by depositing a transparent liquid onto blank background portions (non-image portions) of the paper.
However, according to the technology in Japanese Patent Application Publication No. 2004-58308 and Japanese Patent Application Publication No. 2008-290286, blank background portions are determined from a printed image, and a transparent liquid is simply deposited onto the blank background portions thus determined, and therefore the transparent liquid is deposited even if there is essentially no need to deposit the transparent liquid, thus leading to increased costs.